The feed water for boilers that has now been used is the tap water. But the latter water causes the corrosion of internal engines and pipes for boilers, thus generating scales. This hampers the smooth circulation of feed water and reduces the thermal efficiency of boilers. Also, the precipitation of scales, etc. can cause the problem of stopping and blocking the circulation system. In addition, it can generate the problem of reducing the boiler's lifetime, etc.
In particular, if the boiler is off at a vacant house in winter, internal engines and pipes for boilers may freeze and crack due to the expansion of water. This generates problems such as economic loss including energy loss and the damage in boilers, and inconvenience.
Also, since the thermal conductivity of the tap water is low, the energy loss is high. At the same time, since the evaporation rate of the tap water is very high, the water should be replenished frequently, thus causing inconvenience.